package com.hackerrank.challenges.gameofthrones;

import java.util.Scanner;

public class Solution {
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		char sc[] = in.nextLine().toCharArray();
		int c[] = new int[26], no = 0;
		for(char ch: sc)
			c[ch - 'a']++;
		for(int ci : c)
			if(ci % 2 == 1)
				no++;
		if(sc.length % 2 == no)
			System.out.println("YES");
		else
			System.out.println("NO");
	}
}
